Chapter 3 Powerpoint Cellular Form and Function PDF

Because learning changes everything. ® Chapter 03 Cellular Form and Function ANATOMY & PHYSIOLOGY The Unity of Form and Function TENTH EDITION KENNETH S. SALADIN © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent o...

Because learning changes everything. ® Chapter 03 Cellular Form and Function ANATOMY & PHYSIOLOGY The Unity of Form and Function TENTH EDITION KENNETH S. SALADIN © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.  3.1a Development of the Cell Theory 1 Cytology is the scientific study of cells Generalizations of cells are described by the cell theory: All organisms composed of cells and cell products Cell is the simplest structural and functional unit of life An organism’s structure and functions are due to activities of cells Cells come only from preexisting cells © McGraw Hill, LLC 2  Common Cell Shapes Access the text alternative for slide images. Figure 3.1 © McGraw Hill, LLC 3  Cell Shapes and Sizes 2 Most human cells are about 10 to 15 μm in diameter 1 micrometer (μm), or micron = one-millionth of a meter or one-thousandth of a millimeter Egg cells (very large) = 100 μm diameter Some nerve cells over 1 m long There is a limit on cell size An overly large cell cannot support itself; may rupture For a given increase in diameter, volume increases more than surface area Volume proportional to cube of diameter Surface area proportional to square of diameter © McGraw Hill, LLC 4  The Relationship Between Cell Surface Area and Volume Access the text alternative for slide images. Figure 3.2 © McGraw Hill, LLC 5  Basic Components of a Cell 2 Major components of a cell: Cell is surrounded by a plasma (cell) membrane Defines cell boundaries Made of proteins and lipids Composition can vary between regions of the cell Cytoplasm is within the cell Contains organelles, cytoskeleton, inclusions (stored or foreign particles), and clear gel called the cytosol or intracellular fluid (I C F) Extracellular fluid (E C F) is located outside of cells ECF includes any fluid outside of cells, including tissue (interstitial) fluid, blood plasma, lymph, and cerebrospinal fluid © McGraw Hill, LLC 6  3.2a The Plasma Membrane 1 Plasma membrane defines the boundaries of the cell Appears as pair of dark parallel lines when viewed with electron microscope Has intracellular face and extracellular face a: © Dr. Donald Fawcett/Science Source Access the text alternative for slide images. Figure 3.5a © McGraw Hill, LLC 7  Membrane Lipids 1 Most of membrane (~98%) is composed of lipids, mostly phospholipids Phospholipids 75% of membrane lipids Amphipathic molecules arranged in a bilayer Hydrophilic phosphate heads face water on each side of membrane Hydrophobic tails—are directed toward the center, avoiding water Drift laterally, keeping membrane fluid Cholesterol 20% of the membrane lipids Holds phospholipids still and can stiffen membrane © McGraw Hill, LLC 8  Membrane Lipids 2 Membrane lipids (continued) Glycolipids 5% of the membrane lipids Phospholipids with short carbohydrate chains on extracellular face Contribute to glycocalyx—carbohydrate coating on cell surface © McGraw Hill, LLC 9  The Plasma Membrane 2 Access the text alternative for slide images. Figure 3.5b © McGraw Hill, LLC 10  Membrane Proteins 1 Membrane proteins constitute 2% of the molecules but 50% of the weight of membrane Transmembrane proteins pass completely through membrane Hydrophilic regions contact the watery cytoplasm, extracellular fluid Hydrophobic regions pass through lipid of the membrane Most are glycoproteins Some drift in membrane, others anchored to cytoskeleton Peripheral proteins adhere to one face of the membrane Those on inner face are usually tethered to a transmembrane protein and the cytoskeleton © McGraw Hill, LLC 11  Transmembrane Proteins Access the text alternative for slide images. Figure 3.6 © McGraw Hill, LLC 12  Membrane Proteins 2 Functions of membrane proteins: Receptors—bind chemical signals to trigger internal changes May cause production of a second messenger within cell receiving chemical message Enzymes—catalyze reactions including digestion of molecules, production of second messengers Channel proteins—allow hydrophilic solutes and water to pass through membrane Some are always open, called leak channels, and some are gates (gated channels) that open only when triggered Ligand-gated channels—respond to chemical messengers Voltage-gated channels—respond to charge changes Mechanically gated channels—respond to physical stress on cell © McGraw Hill, LLC 13  Membrane Proteins 3 Functions of membrane proteins (continued): Carriers—bind solutes and transfer them across membrane Pumps—carriers that consume ATP Cell-identity markers—glycoproteins acting as identification tags Cell-adhesion molecules (CAMs)—mechanically link cell to another cell and to extracellular material © McGraw Hill, LLC 14  3.2b The Glycocalyx Glycocalyx—carbohydrate moieties of glycoproteins and glycolipids external to plasma membrane Unique in everyone but identical twins Functions Protection Immunity to infection Defense against cancer Transplant compatibility Cell adhesion Fertilization Embryonic development © McGraw Hill, LLC 15  3.2c Extensions of the Cell Surface 1 Microvilli—extensions (1 to 2 μm) of the membrane that serve to increase surface area Provide 15 to 40 times more surface area to cells that have them Best developed in cells specialized in absorption On some absorptive cells they are very dense and appear as a fringe called the brush border © McGraw Hill, LLC 16  Microvilli and the Glycocalyx (TEM) a: © Don W. Fawcett/Science Source; b: © Biophoto Associates/Science Source Access the text alternative for slide images. Figure 3.9 © McGraw Hill, LLC 17  Extensions of the Cell Surface 2 Cilia—hair-like processes 7 to 10 μm long Single, nonmotile primary cilium found on nearly every cell; serves as “antenna” for monitoring nearby conditions Helps with balance in inner ear; light detection in retina Multiple nonmotile cilia found on sensory cells of nose Motile cilia less widespread Found in respiratory tract, uterine tubes, ventricles of brain, ducts of testes Beat in waves sweeping material across a surface in one direction © McGraw Hill, LLC 18  Cilia 1 a: © Science Photo Library/Alamy Stock Photo Access the text alternative for slide images. Figure 3.10a-b © McGraw Hill, LLC 19  Ciliary Action Access the text alternative for slide images. Figure 3.11 © McGraw Hill, LLC 20  Extensions of the Cell Surface 4 Flagellum—whiplike structure Tail of a sperm is only functional flagellum in humans Whip-like structure Much longer than cilium Stiffened by coarse fibers that support the tail Movement is undulating, snake-like, corkscrew © McGraw Hill, LLC 21  Extensions of the Cell Surface 5 Pseudopods—continually changing extensions of the cell that vary in shape and size Can be used for cellular locomotion, capturing foreign particles Access the text alternative for slide images. Figure 3.12 © McGraw Hill, LLC 22  3.3 Introduction Plasma membrane and organelle membranes are selectively permeable—allowing some things through, but preventing others from passing Passive mechanisms require no ATP Random molecular motion of particles provides necessary energy Filtration, diffusion, osmosis Active mechanisms consume ATP Active transport and vesicular transport © McGraw Hill, LLC 23  3.3a Filtration Filtration—particles are driven through membrane by physical pressure Example: filtration of water and small solutes through gaps between cells or filtration pores in capillary walls Allows delivery of water and nutrients to tissues Allows removal of waste from capillaries in kidneys © McGraw Hill, LLC 24  Filtration Through the Wall of a Blood Capillary Access the text alternative for slide images. Figure 3.13 © McGraw Hill, LLC 25  3.3b Simple Diffusion 1 Simple diffusion—net movement of particles from place of high concentration to place of lower concentration Due to constant, spontaneous molecular motion Molecules collide and bounce off each other Substances diffuse down their concentration gradient From an area of higher concentration to an area of lower concentration Occurs in air, water; does not require a membrane Substance can diffuse through a membrane if the membrane is permeable to the substance © McGraw Hill, LLC 26  Simple Diffusion 2 Simple diffusion (continued) Factors affecting diffusion rate through a membrane: Temperature: ↑ temp., ↑ motion of particles Molecular weight: larger molecules move slower “Steepness” of concentration gradient: ↑ difference, ↑ rate Membrane surface area: ↑ area, ↑ rate Membrane permeability: ↑ permeability, ↑ rate © McGraw Hill, LLC 27  3.3c Osmosis 1 Osmosis—net flow of water through a selectively permeable membrane Water moves from an area of higher water (lower solute) concentration to an area of lower water (higher solute) concentration Water can diffuse through phospholipid bilayers, but osmosis is enhanced by aquaporins—channel proteins in membrane specialized for water passage Cells can speed osmosis by installing more aquaporins Crucial consideration for IV fluids © McGraw Hill, LLC 28  Osmosis 2 Access the text alternative for slide images. Figure 3.14 © McGraw Hill, LLC 29  Osmosis 3 Osmotic pressure—hydrostatic pressure required to stop osmosis Increases as amount of nonpermeating solute rises Nonpermeating solutes cannot pass through membrane Example: proteins Hydrostatic pressure—fluid pressure on the membrane Reverse osmosis—process of applying mechanical pressure to override osmotic pressure Allows purification of water © McGraw Hill, LLC 30  Osmolarity and Tonicity 2 Tonicity Hypotonic solution—causes cell to absorb water, swell, and possibly burst (lyse) Has a lower concentration of nonpermeating solutes than intracellular fluid (ICF) Distilled water is an extreme example Hypertonic solution—causes cell to lose water and shrivel (crenate) Has a higher concentration of nonpermeating solutes than ICF Isotonic solution—causes no change in cell volume Concentrations of nonpermeating solutes in ECF and ICF are the same Normal saline (0.9% NaCl) is an example © McGraw Hill, LLC 31  Effects of Tonicity on RBCs (Hypotonic vs Isotonic) (a-c): © David M. Philips/Science Source Figure 3.15a-b © McGraw Hill, LLC 32  Effects of Tonicity on RBCs (Isotonic vs Hypertonic) (a-c): © David M. Philips/Science Source Figure 3.15b-c © McGraw Hill, LLC 33  3.3e Carrier-Mediated Transport 1 Carrier-mediated transport—proteins (carriers) in cell membrane carry solutes into or out of cell (or organelle) Carriers exhibit specificity for their particular solutes Solute (ligand) binds to receptor site on carrier protein Solute is released unchanged on other side of membrane Carriers also exhibit saturation As solute concentration rises, the rate of transport rises, but only to a point called the transport maximum (Tm ) at which all carriers are occupied © McGraw Hill, LLC 34  Carrier Saturation and Transport Maximum Access the text alternative for slide images. Figure 3.16 © McGraw Hill, LLC 35  Carrier-Mediated Transport 2 There are three kinds of carrier proteins: Uniport—carrier that moves one type of solute Example: calcium pump Symport—carrier that moves two or more solutes simultaneously in same direction (cotransport) Example: sodium–glucose transporters Antiport—carrier that moves two or more solutes in opposite directions (countertransport) Example: sodium–potassium pump removes Na+ , brings in K + Three mechanisms of carrier-mediated transport Facilitated diffusion, primary active transport, secondary active transport © McGraw Hill, LLC 36  Carrier-Mediated Transport 3 There are three mechanisms of carrier-mediated transport: Facilitated diffusion—carrier moves solute down its concentration gradient Does not consume ATP Solute attaches to binding site on carrier, carrier changes conformation, then releases solute on other side of membrane Primary active transport—carrier moves solute through a membrane up its concentration gradient The carrier protein uses ATP for energy Examples: Calcium pump (uniport) uses ATP while expelling calcium from cell to where it is already more concentrated Sodium–potassium pump (antiport) uses ATP while expelling sodium and importing potassium into cell © McGraw Hill, LLC 37  Facilitated Diffusion Access the text alternative for slide images. Figure 3.17 © McGraw Hill, LLC 38  The Sodium–Potassium Pump (Na+–K+ ATPase) Access the text alternative for slide images. Figure 3.19 © McGraw Hill, LLC 39  Carrier-Mediated Transport 4 Mechanisms of carrier-mediated transport (continued) Secondary active transport—carrier moves solute through membrane, but only uses ATP indirectly Example: sodium–glucose transporter (SGLT) Moves glucose into cell, up its concentration gradient, while simultaneously carrying sodium down its gradient Depends on the primary transport performed by sodium- potassium pump Does not itself use ATP © McGraw Hill, LLC 40  Secondary Active Transport Access the text alternative for slide images. Figure 3.18 © McGraw Hill, LLC 41  3.3f Vesicular Transport 1 Vesicular transport moves large particles, fluid droplets, or numerous molecules at once through the membrane in vesicles Vesicles—bubblelike enclosures of membrane Endocytosis brings material into cell; exocytosis releases material from cell Three forms of endocytosis: Phagocytosis—engulfing and destroying large particles; “cell eating” Pseudopods surround object, fuse to form internal phagosome, which merges with lysosome to form phagolysosome within which object is digested Pinocytosis—taking in droplets of ECF containing molecules useful in the cell; pinocytic vesicles in cytoplasm; “cell drinking” Receptor-mediated endocytosis—particles bind to specific receptors on plasma membrane Pit forms in membrane, cytosolic side covered in clathrin protein; forms clathrin- coated vesicle that is directed to destination within cell © McGraw Hill, LLC 42  Phagocytosis, Intracellular Digestion, and Exocytosis Access the text alternative for slide images. Figure 3.20 © McGraw Hill, LLC 43  Receptor- Mediated Endocytosis 1 (1-3): Courtesy of the Company of Biologists, Ltd. Access the text alternative for slide images. Figure 3.21 © McGraw Hill, LLC 44  Receptor- Mediated Endocytosis 2 (1-3): Courtesy of the Company of Biologists, Ltd. Access the text alternative for slide images. Figure 3.21 © McGraw Hill, LLC 45  Receptor- Mediated Endocytosis 3 (1-3): Courtesy of the Company of Biologists, Ltd. Access the text alternative for slide images. Figure 3.21 © McGraw Hill, LLC 46  Vesicular Transport 2 Transcytosis—transport of material across the cell by capturing it on one side and releasing it on the other Example: receptor-mediated endocytosis moves it into the cell and exocytosis moves it out the other side Exocytosis—discharge material from cell Examples: Release of insulin by endocrine cells Sperm cells release enzymes for penetrating egg Mammary gland cells release milk sugar Also functions to replace any plasma membrane lost by endocytosis © McGraw Hill, LLC 47  Transcytosis © Don Fawcett/Science Source Access the text alternative for slide images. Figure 3.22 © McGraw Hill, LLC 48  Exocytosis b: Courtesy of Dr. Birgit Satir, Albert Einstein College of Medicine Access the text alternative for slide images. Figure 3.23 © McGraw Hill, LLC 49  3.4a The Cytosol and Cytoskeleton The cytosol is a clear, viscous, watery material within cell Contains enzymes, other proteins, amino acids, ATP, electrolytes, dissolved gases, metabolic wastes The cytoskeleton is a network of protein filaments and cylinders Functions: Structural support, determines cell shape, organizes cell contents Directs movement of materials within cell and contributes to movements of the cell as a whole Composed of microfilaments, intermediate fibers, microtubules © McGraw Hill, LLC 50  The Cytoskeleton 3 Components of the cytoskeleton: Microfilaments (thin filaments) 6 nm thick; made of actin protein Form terminal web (membrane skeleton) Intermediate filaments 8 to 10 nm thick; within skin cells, made of protein keratin Give cell shape, resist stress Microtubules 25 nm thick; consists of protofilaments made of protein tubulin; radiate from centrosome; can come and go Maintain cell shape, hold organelles, contribute to cilia and flagella, form mitotic spindle © McGraw Hill, LLC 51  Microtubules Access the text alternative for slide images. Figure 3.25 © McGraw Hill, LLC 52  3.4b Organelles Organelles are the internal structures of a cell that carry out specialized metabolic tasks Membranous organelles are surrounded by membranes Nucleus, mitochondria, lysosomes, peroxisomes, endoplasmic reticulum, and Golgi complex Other organelles are without membranes Ribosomes, centrosomes, centrioles, basal bodies © McGraw Hill, LLC 53  The Nucleus 1 The nucleus—usually largest organelle (5 μm in diameter); contains cell’s genetic material Most cells have one; a few types are anuclear (without a nucleus) or multinuclear (have multiple nuclei) Nuclear envelope—double membrane around nucleus Perforated by nuclear pores, each formed by a ring of proteins called the nuclear pore complex Regulate molecular traffic through envelope; hold the two membrane layers together Material within nucleus is called nucleoplasm Includes threadlike chromatin (DNA and proteins) and one or more nucleoli (singular: nucleolus) where ribosomes are produced © McGraw Hill, LLC 54  Structure of the Nucleus Access the text alternative for slide images. Figure 3.27 © McGraw Hill, LLC 55  Endoplasmic Reticulum 1 Endoplasmic reticulum (ER)—network of interconnected membranous channels called cisterns Rough endoplasmic reticulum—parallel, flattened sacs covered with ribosomes Continuous with outer membrane of nuclear envelope Produces phospholipids and proteins of nearly all cell membranes Synthesizes proteins that are packaged in other organelles or secreted from cell Smooth endoplasmic reticulum—tubular ER lacking ribosomes Synthesizes steroids and other lipids Detoxifies alcohol and other drugs Calcium storage © McGraw Hill, LLC 56  Endoplasmic Reticulum 3 Access the text alternative for slide images. Figure 3.28c © McGraw Hill, LLC 57  Ribosomes Ribosomes—small granules of protein and RNA responsible for protein synthesis They “read” coded genetic messages and assemble amino acids into proteins specified by the code Found in nucleoli, in cytosol, on outer surfaces of rough ER, and nuclear envelope © McGraw Hill, LLC 58  Golgi Complex Golgi complex—a system of membranous cisterns that synthesizes carbohydrates and modifies newly synthesized proteins Receives newly synthesized proteins from rough ER Sorts proteins, splices some, adds carbohydrate moieties to some, and packages them into membrane-bound Golgi vesicles Some vesicles become lysosomes Some vesicles migrate to plasma membrane and fuse to it Some become secretory vesicles that store a protein product for later release © McGraw Hill, LLC 59  The Golgi Complex Science History Images/Alamy Stock Photo Access the text alternative for slide images. Figure 3.29 © McGraw Hill, LLC 60  Lysosomes Lysosomes—package of enzymes bound by a membrane Functions: Intracellular hydrolytic digestion of proteins, nucleic acids, complex carbohydrates, phospholipids, and other substances Autophagy—digestion of cell’s surplus organelles Autolysis—digestion of a surplus cell by itself; “cell suicide” © McGraw Hill, LLC 61  Peroxisomes Peroxisomes—resemble lysosomes but contain different enzymes and are produced by endoplasmic reticulum Function is to use molecular oxygen to oxidize organic molecules Reactions produce hydrogen peroxide (H2O2) Catalase breaks down excess peroxide to H2O and O2 Neutralize free radicals, detoxify alcohol, other drugs, and a variety of blood-borne toxins Present in all cells; abundant in liver and kidney © McGraw Hill, LLC 62  Lysosome and Peroxisome EM Research Services, Newcastle University Access the text alternative for slide images. Figure 3.30 © McGraw Hill, LLC 63  Proteasomes Proteasomes—hollow, cylindrical organelles that dispose of surplus proteins Contain enzymes that break down tagged, targeted proteins into short peptides and amino acids © McGraw Hill, LLC 64  Protein Degradation by a Proteasome Access the text alternative for slide images. Figure 3.31 © McGraw Hill, LLC 65  Mitochondria Mitochondria—organelles specialized for synthesizing ATP Continually change shape from spheroidal to thread-like Surrounded by a double membrane Inner membrane has folds called cristae Spaces between cristae called matrix Matrix contains ribosomes, enzymes used for ATP synthesis, and small circular DNA molecules called mitochondrial DNA (mtDNA) “Powerhouses” of the cell Energy is extracted from organic molecules and transferred to ATP © McGraw Hill, LLC 66  A Mitochondrion © Scott Camazine/Alamy Stock Photo Access the text alternative for slide images. Figure 3.32 © McGraw Hill, LLC 67  Centrioles 1 Centriole—a short cylindrical assembly of microtubules arranged in nine groups of three microtubules each Two centrioles lie perpendicular to each other within the centrosome—small clear area in cell Play important role in cell division Form basal bodies of cilia and flagella © McGraw Hill, LLC 68  Centrioles 2 a: © Don W. Fawcett/Science Source Access the text alternative for slide images. Figure 3.33 © McGraw Hill, LLC 69  Inclusions Inclusions—storage products or foreign matter in cytoplasm Accumulated cell products Glycogen granules, pigments, oil droplets Foreign bodies Viruses, intracellular bacteria, dust particles, other debris phagocytized by a cell Never enclosed in a unit membrane Not essential for cell survival © McGraw Hill, LLC 70